M. Pétrequin next makes some remarks on what he terms the elements of the amauroses. It is not the powerless state of the nerve of vision which is to be treated, but the sanguineo-congested condition of the optic apparatus in some cases, its anæmic state in others; it is the sub-inflammatory irritation of the optic nerve, in one instance, its participation in some general dyscrasia, in another, against which our remedies are to be directed. These, and such like elements, as M. Pétrequin chooses to call them, being overcome, if visual asthenia remains, it becomes the object of treatment.

The transformations of the amauroses is the next topic on which M. Pétrequin touches, observing that not only do the amauroses differ from one another, but that even the same amaurosis presents at different periods of its course marked differences in its form and nature. He notices particularly two transformations. The first regards the seat of the disease; for, as it is either on the increase or on the decline, amaurosis may affect more or less extensively the retina and the rest of the optic apparatus. The second regards its nature. Asthenic amaurosis, for example, is rarely primary, but supervenes as a degeneration of the traumatic. The nervous erethistic is transformed into the sanguineous irritative, and this again into the sub-inflammatory. In directing the treatment, the practitioner must bear in view such transitions. M. Pétrequin takes little account seemingly of the difficulty of tracing such transitions. He speaks of them without hesitation as things which can be positively determined, and the treatment changed accordingly.

M. Pétrequin is inclined to believe in an amaurotic myopia. He supposes that as the visual faculty becomes impaired, the sphere of its activity is lessened; or, in other words, that the patient, from an affection of the retina, becomes myopic, with no diminution in the clearness of sight. More frequently, however, this amaurotic myopia is attended with a certain obscurity of vision. Those who are affected in this way, not knowing that they labour under anything more than a shortness of sight, endeavour to relieve themselves by concave glasses of increasing depth. M. Pétrequin has also known some who changed their apartments, fancying the obscurity to be from without, not from within. He remarks, that the phenomena which appear at the outset of the greater number of the amauroses recur on their decline; myopia succeeds amaurosis, as well as precedes it. Hence it is, that the eye does not resume its natural vivacity immediately after the cure of the amaurosis is accomplished; the vision retains a peculiar indecision for a long time; and the physiognomy a sort of stupor, and a characteristic attitude, which is termed the facies amaurotica.

The myopia in question, M. Pétrequin believes to depend, not on any change in the refractive media of the eye, but solely on a vital cause, and he compares it to those morbid states of the other senses, and especially of the ear, in which it is necessary to bring the object much nearer to the organ, than in the healthy condition, to produce the usual impression. With regard to the alleged frequency of relapses in amaurosis, M. Pétrequin remarks, that one cause is to be found in the nature of the disease, and that the original source of the amaurosis may predispose it more or less to relapse, according as it is asthenic, congestive, erethistic,

torpid, or organic. A second cause consists in the perpetual exposure of the organ of vision to external stimuli, which should be avoided by moderating the light, not by excluding it entirely. For this purpose, coloured convex glasses of long focus are recommended by our author, and a long convalescence before the eyes are seriously set to work. The patient should confine himself to seeing for a time, before venturing on the more trying exercise of inspecting. The sympathetic connexions which the eyes have with the other parts of the economy in a state of derangement, is a third cause mentioned by M. Pétrequin, and one which evidently points out the propriety of the strictest attention to the non-naturals.

There is nothing new in the remedies employed by M. Pétrequin. They consist chiefly in bleeding, generally and locally; locally, by leeches round the anus very frequently; purgatives; mercury; counter-irritation; and the endermic employment of strychnia. It is, therefore, to a selection of the proper season for administering the remedies, to a perseverance in their use, and to the having his patients constantly under his observation in an hospital, that the success of M. Pétrequin must be attributed. He ascribes much to the powers of strychnia, which he uses always externally, never internally. What he employs is prepared by M. Pelletier. M. Pétrequin applies it pure, in preference to mixing it up with fatty substances in the form of ointment. As it is applied in doses of a quarter to a third of a grain, a quantity from its smallness apt to be lost, he mixes it with a grain or two of powdered nux vomica. The blister which precedes the application of the strychnia, M. Petrequin forms instantaneously by means of a strong ammoniacal salve. This makes a clean, moist surface, on which to sprinkle the strychnia. At each application afterwards, care is taken to remove the false membrane which has formed in the interval. This, however, is insufficient to prevent the absorption diminishing as the wound dries, so that the doses may be increased, till a new vesication is deemed necessary.

An adjuvant of considerable value is the tincture of nux vomica, prepared with four ounces of the powder to a quart of brandy. This is used for stimulating the branches of the fifth nerve round the orbit, and thus acting sympathetically on the retina.

As strychnia is one of the remedies upon which M. Pétrequin chiefly depends in the treatment of amaurosis, it is important to observe, that it is only when the disease exists in the state of a pure asthenia, that he has recourse to it. The morbid elements which existed in combination with the asthenic state being removed by other means, this stimulant, as it is generally regarded, may be employed with hopes of advantage. M. Pétrequin regards it as an excitant both of the circulating and of the nervous system. It is a remedy, then, to be avoided in congestive or inflammatory cases. These require bleeding, purging, and mercury.

The notion generally entertained respecting nux vomica, and its alcaloid, strychnia, is, that they are powerfully stimulating. This belief is built, first, upon the admission that these substances cure palsies, which are presumed to be asthenic, and second, upon the fact that they give rise to tetanic spasms. Hence the rule, above referred to, that we are to abstain from using strychnia, where there are signs of plethora about the eye or the brain. But the school of Rasori maintain a totally different

doctrine. M. Rognetta, for example, is of opinion that, far from being an excitant, strychnia is a hyposthenisant or sedative, and that it depresses the powers of life, like bleeding or like belladonna. M. Rognetta also asserts that strychnia produces no effect, except by being taken into the circulation. He therefore gives it internally, in the form of an acetate; the dose varying from one twentieth of a grain to half a grain.

We have not hesitated to state very plainly what we consider M. Pétrequin's chief fault. We cannot quit him without noticing one particular which has given us great pleasure in the perusal of his work, namely, his energetic perseverance in endeavouring to accomplish the cure of his patients. We may, perhaps, be permitted to say that this, along with the reputation for success in treating cases of blindness, which he must have acquired, must have powerfully promoted the cure of such a disease as amaurosis- -a nervous disorder, in many instances, of asthenic character, and, therefore, requiring the aid of a beneficial stimulus to the mind, such as that afforded by the exercise of hope, and the confident expectation of relief. We believe that there is perhaps no disease in which moral influences of this kind are of so much importance as amaurosis; while, on the other hand, nothing proves so hurtful, as when the patient is either informed directly, or gathers from the dry, indifferent, inattentive, or repulsive manner of the practitioner, that the disease is hopeless.

ART. X.

1. New Memoir on the true Spinal Marrow, and its Anatomy, Physiology, Pathology, and Therapeutics. By MARSHALL HALL, M.D. F.R.S. L. & E. -Lond. 1843. 4to, pp. 94, with Five Plates.

2. On the Structure, Relations, and Development of the Nervous and Circulatory Systems, and on the Existence of a complete Circulation of the Blood in Vessels, in Myriapoda, and Macrourous Arachnida. First Series. By GEORGE NEWPORT, Esq., President of the Entomological Society of London, Corresponding Member of the Philomathic Society of Paris, &c. 4to, pp. 60, with Five Plates. (From the Second Part of the Philosophical Transactions for 1843.)

I. THE present Memoir, Dr. M. Hall informs us, may be considered as supplementary to his two former Memoirs, published in 1837; and as illustrative of his subsequent volume, on the Diseases and Derangements of the Nervous System,' published in 1841. To us it seems to contain little that is not embodied in his last-mentioned work, save some criticisms upon his critics; and as we have so recently and fully noticed this, we shall confine ourselves on the present occasion to those questions, on which Dr. Hall throws a new light in the memoir before us. We shall, first, however, in justice to him, quote his present statement of his claims, to the general truth of which we fully assent; and if our readers will take the trouble to consult and compare our former articles on the subject, they will find that we can do so without the slightest inconsistency.

"I have reflected with much satisfaction, that, of my various statements, I have scarcely had one to retract, after all the criticism which has been somewhat

lavishly bestowed upon them; and that, of the statements of others, scarcely one has either added anything to what had been done, or has proved correct. [We presume that Dr. M. Hall here refers to the physiological part of his system; the anatomical he has confessedly left to others to work out.] I regard these events as the reward of the care which I had taken to restrain myself within the limits of the most obvious facts, and of the most immediate deductions from those facts. Thus I have restricted the reflex actions to the true spinal marrow. Those who have imagined that a similar reflex function belongs to the cerebral or to the ganglionic system, have, I think, only confused the subject, and added what is really hypothesis or conjecture. I have also confined the part performed by the reflex function within its just limits. Some writers, having extended its influence beyond those limits, have again caused a doubt to be cast over the whole system. In the actions of walking in man, I imagine the reflex function to play a very subsidiary part; although there are, doubtless, facts which demonstrate that the contact of the sole of the foot with the ground is not unattended by a certain influence upon the action of certain muscles. It is very different in the bird and fish tribes, as I shall have occasion to explain hereafter.

"Some writers have taken very unnecessary trouble to prove that the experimental fact of reflex action has long been known to physiologists; as if this had ever been denied, or as if it had not been admitted in the most express terms. (See my First Memoir, § 107.) Others have even descended to show that the term reflex had been employed by former physiologists! (Arnold.) I have never claimed either to have been the first to observe the facts of the reflex action in experiments, or to have been the first to use the term reflex. My real objects have been-First, to separate the reflex actions from any movements resulting from sensation and volition; secondly, to trace these actions to an acknowledged source or principle of action in the animal economy-the vis nervosa of Halleracting according to newly-discovered laws; thirdly, to limit these actions to the true spinal marrow, with its appropriate incident and reflex nerves, exclusively of the cerebral and ganglionic systems; fourthly, to apply the principle of action involved in those facts to physiology-viz. to the physiology of all the acts of exclusion, of ingestion, of retention, and of expulsion, in the animal frame; fifthly, to trace this principle of action in its relation to pathology-viz. to the pathology of the entire class of spasmodic diseases; sixthly, to show its relation to therapeutics, and especially to the action of certain remedial and certain deleterious physical agents; finally, it is to these objects taken together as a whole or as a system, that I prefer my claims; and I do not pretend that an occasional remark may not have been incidentally made by some previous writer, bearing upon some one or more of them." (pp. 4-5.)

"No better idea of the importance of this discovery can be adduced, than the total obscurity and confusion which are observed to prevail in the best works on the nervous system, written previously to its promulgation. In Legallois we have the utmost confusion in regard to sensation and volition, in their relation to their seat in the nervous system and to the reflex motions; in the work of M. Brachet we have the same confusion in reference to the reflex actions and the functions of the ganglionic system; and every physiologist remembers, what is so forcibly expressed by Professor Müller, that this latter part of the nervous system was supposed to explain all the sympathies, whence the designation great sympathetic." (pp. 6-7.)

It is but just to the British school of physiology, however, that we should remark, that the erroneous view last adverted to never prevailed in this country among the best-informed physiologists; and that, although the automatic movements were ordinarily confounded with those in which sensation and volition are concerned, they were attributed to the cerebrospinal system of nerves,-although very far from being properly defined or systematized.

The following is Dr. Hall's general view of the relative amount of the excito-motor power, as possessed by different parts of the nervous system:

"The nervous system may be divided into different portions, according as they are endowed or unendowed with the excito-motor power; thus, in general terms, the cerebrum and cerebellum are in-excitor; the medulla oblongata and medulla spinalis are excitor; the nerves of special sense are in-excitor, the trifacial and the analogous spinal nerves are incident excitor nerves; the nerves distributed to muscles are direct excitors; the ganglionic system is excito-motor, but for reasons which will be given hereafter, in a less prompt and energetic degree. The nervous system may therefore be viewed in its cerebral or in-excitor, its true spinal and excitor, and its ganglionic or slowly-excitor portions. The in-excitor portions of the nervous system coincide with the seat of the mental functions. The excitor portions are chiefly dedicated to the acts of ingestion and egestion. The less excitor or ganglionic portions are the nervous agents in secretion, &c. The true limits of the excito-motor power have been accurately determined by M. Flourens, who also ascertained that whilst this property acts in a direct manner in the medulla oblongata, the medulla spinalis, and the muscular nerves, its action is crossed from the tubercula quadrigemina or, rather, the peduncles." (pp. 17-18.)

Dr. Hall next endeavours to develop his views respecting the new laws of action of the vis nervosa, which he claims to have discovered. On this point, as our readers may recollect, we have on former occasions expressed our inability to discern the novelty of Dr. Hall's doctrines; since it seems to us that the principal change is a verbal one,-namely, his employment of the term vis nervosa in a sense in which it had not been previously used. As, however, he considers the right understanding of the laws in question to lie at the foundation of his physiology, we shall place them before our readers, that they may benefit by them if we cannot.

The vis nervosa of Haller is that power, which, travelling along the nervous trunks, excites the muscles to contraction; and, according to Haller himself, as well as later physiologists, this power acts only in the peripheral direction,—that is, from the centre to the circumference, the roots to the trunks, the trunks to the branches, the branches to the muscles. "The motor power in the nerves," says Professor Müller, “acts only in the direction of the primitive fibres proceeding to the muscles, or in the direction of the ramification of the nerves, and never in a retrograde direction;" and, "all motor fibres act in an isolated manner, from the trunks of the nerves to the smallest ramifications."

"As long," says Dr. Hall, "as these views were entertained by physiologists there could be no application of their principle of action, discovered by experiment, to actual physiology; for, with one exception-that of the tone of the muscular fibre-every physiological action of the vis nervosa or the excito-motor power proceeds along the nerves, in the first instance, in an incident direction from their ramifications towards their trunk, and thence into the true medulla; from and by which latter it is reflected along other nerves in the direction described by the physiologists whom I have quoted. I have ascertained by a series of experiments that the excito-motor power does act in these incident and reflex directions; and I consider the correction of the former error and the establishment of this fact as the first step towards the application of this power to the science of physiology." (pp. 22-3.)

Of the experiments on which Dr. Hall rests his proof of these rather startling positions, we shall cite the one which includes all the rest; giving at the same time a rough imitation of the illustrative diagram.